Buy whatever frame you'd like! I bought mine for 50% off at Hobby Lobby.
Next, find some strong and wide wire mesh. My dad had this in his shop, but I'm sure you could find it at any hardware store.
Next, use a staple gun to attach the mesh to the back of the frame. Use wire cutters to cut off the excess. Ta-da!!!
I love the wide mesh, because earrings with backs just slide right in!